This invention relates to diesel fuels, and more particularly to a low-sulfur content diesel fuel containing an anti-wear, lubricity additive.
In the use of diesel fuels, especially low sulfur content fuels, there is little protection against injector wear. The wear occurs to the injector needle due to rubbing contact with the surface of its container. The wear results in leaking injector fuel pumps. Also, various parts of fuel pumps such as internal gears and cams are subject to wear due to fuel related problems. Excess fuel in the combustion chambers, due to leaking injectors, causes fuel-rich environment with black smoke in the combustion gases.
Also, because of expanded future use of hydrotreated low sulfur diesel fuel for environmental reasons, wear problems with injectors and fuel pumps on trucks/cars will become more noticeable.
Lubricity additives are added to diesel fuel to protect against injector and pump wear. According to the present invention, it has been found that dithiophosphoric diester-dialcohol compounds are useful as anti-wear, lubricity additives in a low-sulfur content diesel fuel. This result was unexpected since it was thought that the lubricity additive in a diesel fuel would not be sufficiently thermally stable to withstand the high temperatures found in the needle valve area of direct injectors used in heavy duty diesel engines.
Thus, it is an object of the present invention to provide a means i.e., an additive, for protecting the moving parts of a diesel injector from wear during operation with a low-sulfur content diesel fuel.